A Turkish military helicopter crashed in the Senoba district of Turkey's southeastern Sirnak province, reports said late on Wednesday.
At least 13 soldiers including a high ranking official were confirmed dead.
The crash occurred as Turkish troops are engaged in operations against the PKK in a mountainous region of Sirnak province.
But a military statement said the crash appeared to be accidental, with initial information indicating that the AS 532 Cougar had hit a high-voltage transmission line shortly after taking off from a base in Sirnak's Senoba region.
"The Cougar type helicopter belonging to our military got tangled in high tension power lines, only three minutes after take off," the statement said.